git.oblomov.eu Git - git/blob - shallow.c

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "tag.h"
   4 #include "pkt-line.h"
   5 #include "remote.h"
   6 #include "refs.h"
   7 #include "sha1-array.h"
   8 #include "diff.h"
   9 #include "revision.h"
  10 #include "commit-slab.h"
  11
  12 static int is_shallow = -1;
  13 static struct stat shallow_stat;
  14 static char *alternate_shallow_file;
  15
  16 void set_alternate_shallow_file(const char *path, int override)
  17 {
  18         if (is_shallow != -1)
  19                 die("BUG: is_repository_shallow must not be called before set_alternate_shallow_file");
  20         if (alternate_shallow_file && !override)
  21                 return;
  22         free(alternate_shallow_file);
  23         alternate_shallow_file = path ? xstrdup(path) : NULL;
  24 }
  25
  26 int register_shallow(const unsigned char *sha1)
  27 {
  28         struct commit_graft *graft =
  29                 xmalloc(sizeof(struct commit_graft));
  30         struct commit *commit = lookup_commit(sha1);
  31
  32         hashcpy(graft->sha1, sha1);
  33         graft->nr_parent = -1;
  34         if (commit && commit->object.parsed)
  35                 commit->parents = NULL;
  36         return register_commit_graft(graft, 0);
  37 }
  38
  39 int is_repository_shallow(void)
  40 {
  41         FILE *fp;
  42         char buf[1024];
  43         const char *path = alternate_shallow_file;
  44
  45         if (is_shallow >= 0)
  46                 return is_shallow;
  47
  48         if (!path)
  49                 path = git_path("shallow");
  50         /*
  51          * fetch-pack sets '--shallow-file ""' as an indicator that no
  52          * shallow file should be used. We could just open it and it
  53          * will likely fail. But let's do an explicit check instead.
  54          */
  55         if (!*path ||
  56             stat(path, &shallow_stat) ||
  57             (fp = fopen(path, "r")) == NULL) {
  58                 is_shallow = 0;
  59                 return is_shallow;
  60         }
  61         is_shallow = 1;
  62
  63         while (fgets(buf, sizeof(buf), fp)) {
  64                 unsigned char sha1[20];
  65                 if (get_sha1_hex(buf, sha1))
  66                         die("bad shallow line: %s", buf);
  67                 register_shallow(sha1);
  68         }
  69         fclose(fp);
  70         return is_shallow;
  71 }
  72
  73 struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
  74                 int shallow_flag, int not_shallow_flag)
  75 {
  76         int i = 0, cur_depth = 0;
  77         struct commit_list *result = NULL;
  78         struct object_array stack = OBJECT_ARRAY_INIT;
  79         struct commit *commit = NULL;
  80         struct commit_graft *graft;
  81
  82         while (commit || i < heads->nr || stack.nr) {
  83                 struct commit_list *p;
  84                 if (!commit) {
  85                         if (i < heads->nr) {
  86                                 commit = (struct commit *)
  87                                         deref_tag(heads->objects[i++].item, NULL, 0);
  88                                 if (!commit || commit->object.type != OBJ_COMMIT) {
  89                                         commit = NULL;
  90                                         continue;
  91                                 }
  92                                 if (!commit->util)
  93                                         commit->util = xmalloc(sizeof(int));
  94                                 *(int *)commit->util = 0;
  95                                 cur_depth = 0;
  96                         } else {
  97                                 commit = (struct commit *)
  98                                         stack.objects[--stack.nr].item;
  99                                 cur_depth = *(int *)commit->util;
 100                         }
 101                 }
 102                 parse_commit_or_die(commit);
 103                 cur_depth++;
 104                 if ((depth != INFINITE_DEPTH && cur_depth >= depth) ||
 105                     (is_repository_shallow() && !commit->parents &&
 106                      (graft = lookup_commit_graft(commit->object.sha1)) != NULL &&
 107                      graft->nr_parent < 0)) {
 108                         commit_list_insert(commit, &result);
 109                         commit->object.flags |= shallow_flag;
 110                         commit = NULL;
 111                         continue;
 112                 }
 113                 commit->object.flags |= not_shallow_flag;
 114                 for (p = commit->parents, commit = NULL; p; p = p->next) {
 115                         if (!p->item->util) {
 116                                 int *pointer = xmalloc(sizeof(int));
 117                                 p->item->util = pointer;
 118                                 *pointer =  cur_depth;
 119                         } else {
 120                                 int *pointer = p->item->util;
 121                                 if (cur_depth >= *pointer)
 122                                         continue;
 123                                 *pointer = cur_depth;
 124                         }
 125                         if (p->next)
 126                                 add_object_array(&p->item->object,
 127                                                 NULL, &stack);
 128                         else {
 129                                 commit = p->item;
 130                                 cur_depth = *(int *)commit->util;
 131                         }
 132                 }
 133         }
 134
 135         return result;
 136 }
 137
 138 void check_shallow_file_for_update(void)
 139 {
 140         struct stat st;
 141
 142         if (!is_shallow)
 143                 return;
 144         else if (is_shallow == -1)
 145                 die("BUG: shallow must be initialized by now");
 146
 147         if (stat(git_path("shallow"), &st))
 148                 die("shallow file was removed during fetch");
 149         else if (st.st_mtime != shallow_stat.st_mtime
 150 #ifdef USE_NSEC
 151                  || ST_MTIME_NSEC(st) != ST_MTIME_NSEC(shallow_stat)
 152 #endif
 153                    )
 154                 die("shallow file was changed during fetch");
 155 }
 156
 157 #define SEEN_ONLY 1
 158 #define VERBOSE   2
 159
 160 struct write_shallow_data {
 161         struct strbuf *out;
 162         int use_pack_protocol;
 163         int count;
 164         unsigned flags;
 165 };
 166
 167 static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
 168 {
 169         struct write_shallow_data *data = cb_data;
 170         const char *hex = sha1_to_hex(graft->sha1);
 171         if (graft->nr_parent != -1)
 172                 return 0;
 173         if (data->flags & SEEN_ONLY) {
 174                 struct commit *c = lookup_commit(graft->sha1);
 175                 if (!c || !(c->object.flags & SEEN)) {
 176                         if (data->flags & VERBOSE)
 177                                 printf("Removing %s from .git/shallow\n",
 178                                        sha1_to_hex(c->object.sha1));
 179                         return 0;
 180                 }
 181         }
 182         data->count++;
 183         if (data->use_pack_protocol)
 184                 packet_buf_write(data->out, "shallow %s", hex);
 185         else {
 186                 strbuf_addstr(data->out, hex);
 187                 strbuf_addch(data->out, '\n');
 188         }
 189         return 0;
 190 }
 191
 192 static int write_shallow_commits_1(struct strbuf *out, int use_pack_protocol,
 193                                    const struct sha1_array *extra,
 194                                    unsigned flags)
 195 {
 196         struct write_shallow_data data;
 197         int i;
 198         data.out = out;
 199         data.use_pack_protocol = use_pack_protocol;
 200         data.count = 0;
 201         data.flags = flags;
 202         for_each_commit_graft(write_one_shallow, &data);
 203         if (!extra)
 204                 return data.count;
 205         for (i = 0; i < extra->nr; i++) {
 206                 strbuf_addstr(out, sha1_to_hex(extra->sha1[i]));
 207                 strbuf_addch(out, '\n');
 208                 data.count++;
 209         }
 210         return data.count;
 211 }
 212
 213 int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
 214                           const struct sha1_array *extra)
 215 {
 216         return write_shallow_commits_1(out, use_pack_protocol, extra, 0);
 217 }
 218
 219 char *setup_temporary_shallow(const struct sha1_array *extra)
 220 {
 221         struct strbuf sb = STRBUF_INIT;
 222         int fd;
 223
 224         if (write_shallow_commits(&sb, 0, extra)) {
 225                 struct strbuf path = STRBUF_INIT;
 226                 strbuf_addstr(&path, git_path("shallow_XXXXXX"));
 227                 fd = xmkstemp(path.buf);
 228                 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
 229                         die_errno("failed to write to %s",
 230                                   path.buf);
 231                 close(fd);
 232                 strbuf_release(&sb);
 233                 return strbuf_detach(&path, NULL);
 234         }
 235         /*
 236          * is_repository_shallow() sees empty string as "no shallow
 237          * file".
 238          */
 239         return xstrdup("");
 240 }
 241
 242 void setup_alternate_shallow(struct lock_file *shallow_lock,
 243                              const char **alternate_shallow_file,
 244                              const struct sha1_array *extra)
 245 {
 246         struct strbuf sb = STRBUF_INIT;
 247         int fd;
 248
 249         check_shallow_file_for_update();
 250         fd = hold_lock_file_for_update(shallow_lock, git_path("shallow"),
 251                                        LOCK_DIE_ON_ERROR);
 252         if (write_shallow_commits(&sb, 0, extra)) {
 253                 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
 254                         die_errno("failed to write to %s",
 255                                   shallow_lock->filename);
 256                 *alternate_shallow_file = shallow_lock->filename;
 257         } else
 258                 /*
 259                  * is_repository_shallow() sees empty string as "no
 260                  * shallow file".
 261                  */
 262                 *alternate_shallow_file = "";
 263         strbuf_release(&sb);
 264 }
 265
 266 static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
 267 {
 268         int fd = *(int *)cb;
 269         if (graft->nr_parent == -1)
 270                 packet_write(fd, "shallow %s\n", sha1_to_hex(graft->sha1));
 271         return 0;
 272 }
 273
 274 void advertise_shallow_grafts(int fd)
 275 {
 276         if (!is_repository_shallow())
 277                 return;
 278         for_each_commit_graft(advertise_shallow_grafts_cb, &fd);
 279 }
 280
 281 /*
 282  * mark_reachable_objects() should have been run prior to this and all
 283  * reachable commits marked as "SEEN".
 284  */
 285 void prune_shallow(int show_only)
 286 {
 287         static struct lock_file shallow_lock;
 288         struct strbuf sb = STRBUF_INIT;
 289         int fd;
 290
 291         if (show_only) {
 292                 write_shallow_commits_1(&sb, 0, NULL, SEEN_ONLY | VERBOSE);
 293                 strbuf_release(&sb);
 294                 return;
 295         }
 296         check_shallow_file_for_update();
 297         fd = hold_lock_file_for_update(&shallow_lock, git_path("shallow"),
 298                                        LOCK_DIE_ON_ERROR);
 299         if (write_shallow_commits_1(&sb, 0, NULL, SEEN_ONLY)) {
 300                 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
 301                         die_errno("failed to write to %s",
 302                                   shallow_lock.filename);
 303                 commit_lock_file(&shallow_lock);
 304         } else {
 305                 unlink(git_path("shallow"));
 306                 rollback_lock_file(&shallow_lock);
 307         }
 308         strbuf_release(&sb);
 309 }
 310
 311 #define TRACE_KEY "GIT_TRACE_SHALLOW"
 312
 313 /*
 314  * Step 1, split sender shallow commits into "ours" and "theirs"
 315  * Step 2, clean "ours" based on .git/shallow
 316  */
 317 void prepare_shallow_info(struct shallow_info *info, struct sha1_array *sa)
 318 {
 319         int i;
 320         trace_printf_key(TRACE_KEY, "shallow: prepare_shallow_info\n");
 321         memset(info, 0, sizeof(*info));
 322         info->shallow = sa;
 323         if (!sa)
 324                 return;
 325         info->ours = xmalloc(sizeof(*info->ours) * sa->nr);
 326         info->theirs = xmalloc(sizeof(*info->theirs) * sa->nr);
 327         for (i = 0; i < sa->nr; i++) {
 328                 if (has_sha1_file(sa->sha1[i])) {
 329                         struct commit_graft *graft;
 330                         graft = lookup_commit_graft(sa->sha1[i]);
 331                         if (graft && graft->nr_parent < 0)
 332                                 continue;
 333                         info->ours[info->nr_ours++] = i;
 334                 } else
 335                         info->theirs[info->nr_theirs++] = i;
 336         }
 337 }
 338
 339 void clear_shallow_info(struct shallow_info *info)
 340 {
 341         free(info->ours);
 342         free(info->theirs);
 343 }
 344
 345 /* Step 4, remove non-existent ones in "theirs" after getting the pack */
 346
 347 void remove_nonexistent_theirs_shallow(struct shallow_info *info)
 348 {
 349         unsigned char (*sha1)[20] = info->shallow->sha1;
 350         int i, dst;
 351         trace_printf_key(TRACE_KEY, "shallow: remove_nonexistent_theirs_shallow\n");
 352         for (i = dst = 0; i < info->nr_theirs; i++) {
 353                 if (i != dst)
 354                         info->theirs[dst] = info->theirs[i];
 355                 if (has_sha1_file(sha1[info->theirs[i]]))
 356                         dst++;
 357         }
 358         info->nr_theirs = dst;
 359 }
 360
 361 define_commit_slab(ref_bitmap, uint32_t *);
 362
 363 struct paint_info {
 364         struct ref_bitmap ref_bitmap;
 365         unsigned nr_bits;
 366         char **slab;
 367         char *free, *end;
 368         unsigned slab_count;
 369 };
 370
 371 static uint32_t *paint_alloc(struct paint_info *info)
 372 {
 373         unsigned nr = (info->nr_bits + 31) / 32;
 374         unsigned size = nr * sizeof(uint32_t);
 375         void *p;
 376         if (!info->slab_count || info->free + size > info->end) {
 377                 info->slab_count++;
 378                 info->slab = xrealloc(info->slab,
 379                                       info->slab_count * sizeof(*info->slab));
 380                 info->free = xmalloc(COMMIT_SLAB_SIZE);
 381                 info->slab[info->slab_count - 1] = info->free;
 382                 info->end = info->free + COMMIT_SLAB_SIZE;
 383         }
 384         p = info->free;
 385         info->free += size;
 386         return p;
 387 }
 388
 389 /*
 390  * Given a commit SHA-1, walk down to parents until either SEEN,
 391  * UNINTERESTING or BOTTOM is hit. Set the id-th bit in ref_bitmap for
 392  * all walked commits.
 393  */
 394 static void paint_down(struct paint_info *info, const unsigned char *sha1,
 395                        int id)
 396 {
 397         unsigned int i, nr;
 398         struct commit_list *head = NULL;
 399         int bitmap_nr = (info->nr_bits + 31) / 32;
 400         int bitmap_size = bitmap_nr * sizeof(uint32_t);
 401         uint32_t *tmp = xmalloc(bitmap_size); /* to be freed before return */
 402         uint32_t *bitmap = paint_alloc(info);
 403         struct commit *c = lookup_commit_reference_gently(sha1, 1);
 404         if (!c)
 405                 return;
 406         memset(bitmap, 0, bitmap_size);
 407         bitmap[id / 32] |= (1 << (id % 32));
 408         commit_list_insert(c, &head);
 409         while (head) {
 410                 struct commit_list *p;
 411                 struct commit *c = head->item;
 412                 uint32_t **refs = ref_bitmap_at(&info->ref_bitmap, c);
 413
 414                 p = head;
 415                 head = head->next;
 416                 free(p);
 417
 418                 /* XXX check "UNINTERESTING" from pack bitmaps if available */
 419                 if (c->object.flags & (SEEN | UNINTERESTING))
 420                         continue;
 421                 else
 422                         c->object.flags |= SEEN;
 423
 424                 if (*refs == NULL)
 425                         *refs = bitmap;
 426                 else {
 427                         memcpy(tmp, *refs, bitmap_size);
 428                         for (i = 0; i < bitmap_nr; i++)
 429                                 tmp[i] |= bitmap[i];
 430                         if (memcmp(tmp, *refs, bitmap_size)) {
 431                                 *refs = paint_alloc(info);
 432                                 memcpy(*refs, tmp, bitmap_size);
 433                         }
 434                 }
 435
 436                 if (c->object.flags & BOTTOM)
 437                         continue;
 438
 439                 if (parse_commit(c))
 440                         die("unable to parse commit %s",
 441                             sha1_to_hex(c->object.sha1));
 442
 443                 for (p = c->parents; p; p = p->next) {
 444                         uint32_t **p_refs = ref_bitmap_at(&info->ref_bitmap,
 445                                                           p->item);
 446                         if (p->item->object.flags & SEEN)
 447                                 continue;
 448                         if (*p_refs == NULL || *p_refs == *refs)
 449                                 *p_refs = *refs;
 450                         commit_list_insert(p->item, &head);
 451                 }
 452         }
 453
 454         nr = get_max_object_index();
 455         for (i = 0; i < nr; i++) {
 456                 struct object *o = get_indexed_object(i);
 457                 if (o && o->type == OBJ_COMMIT)
 458                         o->flags &= ~SEEN;
 459         }
 460
 461         free(tmp);
 462 }
 463
 464 static int mark_uninteresting(const char *refname,
 465                               const unsigned char *sha1,
 466                               int flags, void *cb_data)
 467 {
 468         struct commit *commit = lookup_commit_reference_gently(sha1, 1);
 469         if (!commit)
 470                 return 0;
 471         commit->object.flags |= UNINTERESTING;
 472         mark_parents_uninteresting(commit);
 473         return 0;
 474 }
 475
 476 static void post_assign_shallow(struct shallow_info *info,
 477                                 struct ref_bitmap *ref_bitmap,
 478                                 int *ref_status);
 479 /*
 480  * Step 6(+7), associate shallow commits with new refs
 481  *
 482  * info->ref must be initialized before calling this function.
 483  *
 484  * If used is not NULL, it's an array of info->shallow->nr
 485  * bitmaps. The n-th bit set in the m-th bitmap if ref[n] needs the
 486  * m-th shallow commit from info->shallow.
 487  *
 488  * If used is NULL, "ours" and "theirs" are updated. And if ref_status
 489  * is not NULL it's an array of ref->nr ints. ref_status[i] is true if
 490  * the ref needs some shallow commits from either info->ours or
 491  * info->theirs.
 492  */
 493 void assign_shallow_commits_to_refs(struct shallow_info *info,
 494                                     uint32_t **used, int *ref_status)
 495 {
 496         unsigned char (*sha1)[20] = info->shallow->sha1;
 497         struct sha1_array *ref = info->ref;
 498         unsigned int i, nr;
 499         int *shallow, nr_shallow = 0;
 500         struct paint_info pi;
 501
 502         trace_printf_key(TRACE_KEY, "shallow: assign_shallow_commits_to_refs\n");
 503         shallow = xmalloc(sizeof(*shallow) * (info->nr_ours + info->nr_theirs));
 504         for (i = 0; i < info->nr_ours; i++)
 505                 shallow[nr_shallow++] = info->ours[i];
 506         for (i = 0; i < info->nr_theirs; i++)
 507                 shallow[nr_shallow++] = info->theirs[i];
 508
 509         /*
 510          * Prepare the commit graph to track what refs can reach what
 511          * (new) shallow commits.
 512          */
 513         nr = get_max_object_index();
 514         for (i = 0; i < nr; i++) {
 515                 struct object *o = get_indexed_object(i);
 516                 if (!o || o->type != OBJ_COMMIT)
 517                         continue;
 518
 519                 o->flags &= ~(UNINTERESTING | BOTTOM | SEEN);
 520         }
 521
 522         memset(&pi, 0, sizeof(pi));
 523         init_ref_bitmap(&pi.ref_bitmap);
 524         pi.nr_bits = ref->nr;
 525
 526         /*
 527          * "--not --all" to cut short the traversal if new refs
 528          * connect to old refs. If not (e.g. force ref updates) it'll
 529          * have to go down to the current shallow commits.
 530          */
 531         head_ref(mark_uninteresting, NULL);
 532         for_each_ref(mark_uninteresting, NULL);
 533
 534         /* Mark potential bottoms so we won't go out of bound */
 535         for (i = 0; i < nr_shallow; i++) {
 536                 struct commit *c = lookup_commit(sha1[shallow[i]]);
 537                 c->object.flags |= BOTTOM;
 538         }
 539
 540         for (i = 0; i < ref->nr; i++)
 541                 paint_down(&pi, ref->sha1[i], i);
 542
 543         if (used) {
 544                 int bitmap_size = ((pi.nr_bits + 31) / 32) * sizeof(uint32_t);
 545                 memset(used, 0, sizeof(*used) * info->shallow->nr);
 546                 for (i = 0; i < nr_shallow; i++) {
 547                         const struct commit *c = lookup_commit(sha1[shallow[i]]);
 548                         uint32_t **map = ref_bitmap_at(&pi.ref_bitmap, c);
 549                         if (*map)
 550                                 used[shallow[i]] = xmemdupz(*map, bitmap_size);
 551                 }
 552                 /*
 553                  * unreachable shallow commits are not removed from
 554                  * "ours" and "theirs". The user is supposed to run
 555                  * step 7 on every ref separately and not trust "ours"
 556                  * and "theirs" any more.
 557                  */
 558         } else
 559                 post_assign_shallow(info, &pi.ref_bitmap, ref_status);
 560
 561         clear_ref_bitmap(&pi.ref_bitmap);
 562         for (i = 0; i < pi.slab_count; i++)
 563                 free(pi.slab[i]);
 564         free(pi.slab);
 565         free(shallow);
 566 }
 567
 568 struct commit_array {
 569         struct commit **commits;
 570         int nr, alloc;
 571 };
 572
 573 static int add_ref(const char *refname,
 574                    const unsigned char *sha1, int flags, void *cb_data)
 575 {
 576         struct commit_array *ca = cb_data;
 577         ALLOC_GROW(ca->commits, ca->nr + 1, ca->alloc);
 578         ca->commits[ca->nr] = lookup_commit_reference_gently(sha1, 1);
 579         if (ca->commits[ca->nr])
 580                 ca->nr++;
 581         return 0;
 582 }
 583
 584 static void update_refstatus(int *ref_status, int nr, uint32_t *bitmap)
 585 {
 586         int i;
 587         if (!ref_status)
 588                 return;
 589         for (i = 0; i < nr; i++)
 590                 if (bitmap[i / 32] & (1 << (i % 32)))
 591                         ref_status[i]++;
 592 }
 593
 594 /*
 595  * Step 7, reachability test on "ours" at commit level
 596  */
 597 static void post_assign_shallow(struct shallow_info *info,
 598                                 struct ref_bitmap *ref_bitmap,
 599                                 int *ref_status)
 600 {
 601         unsigned char (*sha1)[20] = info->shallow->sha1;
 602         struct commit *c;
 603         uint32_t **bitmap;
 604         int dst, i, j;
 605         int bitmap_nr = (info->ref->nr + 31) / 32;
 606         struct commit_array ca;
 607
 608         trace_printf_key(TRACE_KEY, "shallow: post_assign_shallow\n");
 609         if (ref_status)
 610                 memset(ref_status, 0, sizeof(*ref_status) * info->ref->nr);
 611
 612         /* Remove unreachable shallow commits from "theirs" */
 613         for (i = dst = 0; i < info->nr_theirs; i++) {
 614                 if (i != dst)
 615                         info->theirs[dst] = info->theirs[i];
 616                 c = lookup_commit(sha1[info->theirs[i]]);
 617                 bitmap = ref_bitmap_at(ref_bitmap, c);
 618                 if (!*bitmap)
 619                         continue;
 620                 for (j = 0; j < bitmap_nr; j++)
 621                         if (bitmap[0][j]) {
 622                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
 623                                 dst++;
 624                                 break;
 625                         }
 626         }
 627         info->nr_theirs = dst;
 628
 629         memset(&ca, 0, sizeof(ca));
 630         head_ref(add_ref, &ca);
 631         for_each_ref(add_ref, &ca);
 632
 633         /* Remove unreachable shallow commits from "ours" */
 634         for (i = dst = 0; i < info->nr_ours; i++) {
 635                 if (i != dst)
 636                         info->ours[dst] = info->ours[i];
 637                 c = lookup_commit(sha1[info->ours[i]]);
 638                 bitmap = ref_bitmap_at(ref_bitmap, c);
 639                 if (!*bitmap)
 640                         continue;
 641                 for (j = 0; j < bitmap_nr; j++)
 642                         if (bitmap[0][j] &&
 643                             /* Step 7, reachability test at commit level */
 644                             !in_merge_bases_many(c, ca.nr, ca.commits)) {
 645                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
 646                                 dst++;
 647                                 break;
 648                         }
 649         }
 650         info->nr_ours = dst;
 651
 652         free(ca.commits);
 653 }
 654
 655 /* (Delayed) step 7, reachability test at commit level */
 656 int delayed_reachability_test(struct shallow_info *si, int c)
 657 {
 658         if (si->need_reachability_test[c]) {
 659                 struct commit *commit = lookup_commit(si->shallow->sha1[c]);
 660
 661                 if (!si->commits) {
 662                         struct commit_array ca;
 663                         memset(&ca, 0, sizeof(ca));
 664                         head_ref(add_ref, &ca);
 665                         for_each_ref(add_ref, &ca);
 666                         si->commits = ca.commits;
 667                         si->nr_commits = ca.nr;
 668                 }
 669
 670                 si->reachable[c] = in_merge_bases_many(commit,
 671                                                        si->nr_commits,
 672                                                        si->commits);
 673                 si->need_reachability_test[c] = 0;
 674         }
 675         return si->reachable[c];
 676 }